The present invention relates to wiper devices and liquid ejection apparatus.
Inkjet type printers (hereafter simply referred to as printers) are widely known as liquid ejection apparatuses that eject ink (liquid) onto a target from a recording head, or a liquid ejection head having a plurality of nozzles. After having been ejected, the ink may adhere to a portion in the vicinity of nozzle openings. Also, after having been ejected, ink may be splashed by a target (for example, recording medium, such as a sheet of paper), thus adhering to a nozzle surface of the recording head. Ink adhered to the nozzle surface can cause offset ejection of ink droplets or clogging of the nozzles. This leads to printing problems. In order to solve these problems, printers are typically provided with a wiper device that wipes the nozzle surface of the recording head, thereby cleaning the nozzle surface.
This type of printer has a cap holder that covers the nozzle surface of the recording head to prevent the recording head from being dry. A wiping device includes a rubber wiper member that is selectively raised and lowered relative to the cap holder. In wiping operation, the vertical position of the wiper member is controlled such that the distal end (upper end) of the wiper member overlaps the nozzle surface by an amount of approximately 1 mm. The recording head is moved horizontally relative to the wiper member. The relative movement causes the distal end (upper end) of the wiper member to be flexed and slide on the nozzle surface of the recording head. Accordingly, ink on the nozzle surface is wiped off.
A typical recording head has a box-like head case attached to the lower surface of a carriage, and a rectangular nozzle plate provided on the lower surface of the head case. JP-A-2001-260383 discloses a configuration in which the edge of at least one of the four sides of a nozzle plate is supported from below by a support portion of a head cover so that the nozzle plate does not come off the head case.
The support portion of the cover head forms a step on the nozzle surface disclosed in JP-A-2001-260383. Thus, when the wiper member wipes the nozzle surface, ink adhered about the step is not sufficiently removed. That is, some ink remains unwiped on the nozzle surface.
To permit the wiper member to wipe off the ink in an area including the step on the nozzle surface, it may be effective to increase the rigidity of the wiper member and the urging force with which the wiper member is pressed against the nozzle surface. In this case, however, the pressing force by which the wiper member is pressed against the nozzle surface can be excessively increased. The wiper member can thus remove water-repellent plating on the nozzle surface (particularly, the plating in an area including the nozzle openings). Also, the sliding resistance between the wiper member and the nozzle surface can be excessively great, which increases the driving load for moving the recording head and the wiper member relative to each other.